System for Fastening a Rail to a fixed Bottom Support, and Fastener for a Rail

ABSTRACT

The invention provides a system for fastening a rail in place and a rail fastener which, while being simple to install, allow a large measure of freedom in the production of the components required and at the same time have great practical utility. To this end a system according to the invention for fastening a rail to a fixed bottom support: a base plate produced from a plastics material, an intermediate layer which is arranged between the base plate and the fixed bottom support, a carrier plate which is arranged between the intermediate layer and the bottom support, a resilient member to hold down the rail which is to be fastened in place, a clamping bolt to brace the resilient member against the base plate, and a fastening member for fastening the base plate to the fixed bottom support.

The invention relates to a system for fastening a rail to a fixed bottomsupport which is typically formed by a concrete sleeper or a concreteslab. Such systems are intended to be inexpensive to manufacture, to beable to be installed easily and at the same time to function safely andreliably for as long a time as possible.

Known in practice is a rail fastening system offered under the name“ECF” in which the rail stands on the supporting surface of a base platemade of steel. At its longitudinal sides which are aligned in thelongitudinal direction of the rail which is to be fastened in place, thesupporting surface is bounded by respective ribs against which the footof the rail is guided laterally when in the fully installed state. Therib also acts as a mounting for a clamping bolt whose head seats bypositive-fit in a receptacle formed or moulded in the rib and whoseshank passes through the central loop of a W-shaped clamping clip in thedirection pointing away from the upper side of the base plate. By meansof a nut which is screwed onto the clamping bolt, the clamping clip isthen braced against the base plate in such a way that a sufficientlyhigh hold-down force is exerted on the given side of the foot of therail by the free ends of the resilient arms of the clamping clip.

It is ensured in this case that a rail fastener formed by the ECF systemhas an adequate ability to yield when a railway vehicle travels over itby an elastic intermediate layer, which intermediate layer is arrangedbetween the base plate and a carrier plate which rests on whatever isthe solid support in the given case.

To enable the position of the rail to be adjusted to whatever trackgauge is required in the given case, there are formed or moulded in theECF system, in the regions of the base plate which project laterallybeyond the supporting surface, respective openings for sleeves, whichopenings run from the upper sides of the regions to their undersides andhave seated in them eccentric sleeves which are designed to formhold-down sleeves. At its end which is at the top in the installedposition, the eccentric sleeve has, in this case, a projection in theform of a collar which extends round the circumferential face of thesleeve and which rests on the upper face of the base plate in theinstalled position. At the same time, the heightwise distance leftbetween the underside of the projecting collar and that end of theeccentric sleeve which is at the bottom in the installed position is ofa size such that the sleeve stands on the carrier plate in the fullyinstalled state. Inserted through the opening for the eccentric sleevein this case is a bolt which is screwed into an anchor inset into thefixed bottom support and which thus creates an axis of rotation for thesleeve. What is achieved by this design is on the one hand that the baseplate is braced against the fixed bottom support with a definedhold-down force by means of the eccentric sleeve which acts as ahold-down device. On the other hand, the position of the base plate, andwith it the rail standing on it, can be shifted in a direction at rightangles to the longitudinal extent of the rail by turning the eccentricsleeve, in order to adjust the position of the rail to the track gaugerequired.

It is a disadvantage of the known ECF system for fastening a rail inplace that the base plate is high in weight and also limits the freedomwhich exists when designing and configuring it because of the steelmaterial which is used to produce it.

To avoid the disadvantages of base plates of the kind explained abovemade of steel, it has been proposed that base plates of this kind bemade from plastics material. An example of a base plate of this kind isdisclosed in EP 1 950 347 A2. The base plate described therein has, onits underside which is associated with the fixed bottom support, astiffening structure which is formed by intersecting ribs which betweenthem define respective unfilled recesses. In addition, there are formedor moulded in the base plate through-openings through which a bolt ofconventional hexagon-head form can be inserted from the underside of thebase plate to act as a clamping bolt to brace a clamping clip againstthe base plate. For the head of the clamping bolt, there is provided inthis case a receptacle which is formed or moulded in the underside ofthe base plate and which is likewise of a hexagonal form and in whichthe head of the bolt is seated with positive-fit in the fully installedstate.

The base plate known from EP 1 950 347 A2, which is composed of plasticsmaterial, is intended to be laid down directly on whatever is the fixedbottom support in the given case. To enable a sufficiently firm hold tobe obtained, the known base plate is provided at each of its narrowsides with three through-openings through each of which a fastening boltwhich can be screwed into the solid bottom support is inserted. Noprovision is made in this case either for any adjustment of the trackgauge or for the rail to be elastically mounted.

Against the background of the prior art described above, the object ofthe invention was to provide a system for fastening a rail in place anda rail fastener which, while being simple to install, would allow alarge measure of freedom in the production of the components requiredand at the same time have great practical utility.

In accordance with the invention, this object has been achieved by asystem formed as defined in claim 1 for fastening a rail to a fixedbottom support and by a fastener for a rail which is produced by using asystem according to the invention. Advantageous embodiments of a systemaccording to the invention are specified in the claims which arereferred back to claim 1 and they will be explained in what follows.

A rail fastening system according to the invention therefore comprises abase plate produced from a plastics material. Producing the base platefrom plastics material on the one hand achieves an appreciable saving inweight in comparison with the known base plates made of steel or castiron. In addition, the use of plastics material is a simple way ofenabling shapes to be formed on the base plate which cannot bereproduced in steel or similar materials.

It is also of particular importance to the invention that in theinstalled state the base plate produced from plastics material stands onan intermediate layer which is arranged between the base plate and thefixed bottom support. This enables to make use of the elasticity of anintermediate layer of comparably large volume and to give the fastenerproduced by the system according to the invention, when a railwayvehicle travels over it, a yield which, as exactly as possible, can bedetermined in advance.

On the one hand to ensure that the support which the rail has on thefixed bottom support is as even as possible, but on the other hand toalso minimise the abrasive wear on the elastic intermediate layer, thereis provided in addition in a fastening system according to the inventiona carrier plate which is to be arranged between the intermediate layerand the fixed bottom support. This can if required be made of comparablythin steel sheet or of a sufficiently strong plastics material.

A system according to the invention also includes a resilient memberwhich, in a known manner, applies the resilient force required to holddown the rail which is to be fastened in place. To brace the resilientmember, there is provided in this case, as is also known and usual, aclamping bolt to brace the resilient member to the base plate.

Finally, the system according to the invention also comprises at leastone fastening member for fastening the base plate to the fixed bottomsupport, at least two or four such fastening members usually beingrequired to anchor a rail fastening formed in accordance with theinvention safely and securely to whatever is the fixed bottom support inthe given case.

What the combination according to the invention of a base plate made ofplastics material and an elastic layer carrying it thus makes availableis a rail fastening system or a correspondingly composed fastener for arail which is not only able to be installed in a particularly easy waydue to the minimised weight of its individual parts, and particularly ofits base plate, but which also shows yielding behaviour, particularlywell suited for practical requirements, when a railway vehicle travelsover it.

Formed or moulded in the base plate there may be at least one openingfor a hold-down sleeve, which opening runs from the upper side of thebase plate to its underside and in which opening for a sleeve ahold-down sleeve is put in a sliding fit, the height of which hold-downsleeve is greater than the thickness of the base plate in the region ofthe opening for a sleeve associated with it and which hold-down sleevehas a projection protruding from its circumferential surface which bearsagainst the upper side of the base plate in the fully installed state,the fastening member then being intended in this case to be insertedthrough the opening of the hold-down sleeve. What the hold-down sleeveinserted in the opening for the sleeve does in this embodiment, in a waycomparable to the prior art explained above, is to cause the base plateto be loaded only by a preset maximum force. This is a safe and certainway of preventing the base plate made of plastics material from beingdamaged by errors at the time of installation. At the same time, thesleeve also ensures that the elastic intermediate layer is onlycompressed by the fastening member so far as is required to give it asecure and reliable grip. In this way, the elasticity which the elasticintermediate layer is required to provide is reliably available even inthe fully installed state. The sliding fit which the sleeve has in itsassociated opening in the base plate ensures in this case that the baseplate is able to follow unhindered any compression or expansion of theintermediate layer which occurs as a result of the loads applied whentravel takes place over it.

Basically, a system according to the invention is just as suitable asthe prior art for an adjustment of track gauge performed with the helpof an eccentric sleeve. To enable use to be made of this opportunity foradjustment, the hold-down sleeve may take the form of an eccentricsleeve. In order in this case to enable a check to be made on theadjustment which is effected in the given case, which check isparticularly simple and is adapted to the rough conditions which mayarise on the given site, there may be formed, in the opening for thesleeve, markers for indexing which are arranged at a spacing from oneanother such that, allowing for the eccentricity of the axis of rotationof the eccentric sleeve from the central longitudinal axis of theopening for the sleeve, the markers for indexing define positions inrotation of the eccentric sleeve if the eccentric sleeve is adjusted inrotation about its axis of rotation in the opening for the sleeve, whichpositions in rotation correspond to a step-by-step change in theposition of the base plate by a defined amount. Because the hold-downsleeve has a shaped member compatible with the markers for indexing inthe opening for the sleeve by means of which shaped member the hold-downsleeve inserted in the opening for a sleeve associated with the saidhold-down sleeve is coupled by positive-fit to a given one of themarkers for indexing in the opening for the sleeve, the position of thebase plate can be adjusted without any problems in a way which is easyto follow for the installer in such a way that an adjustment of thetrack gauge to an ideally correct size is obtained without anyburdensome measurements.

The indexable locking of the eccentric sleeve to the base plate whichfixes the given position in rotation of the eccentric sleeve may beperformed by means of a shaped member formed on the eccentric sleevewhich is compatible with the shape of the marker for indexing. Dependingon the location of the shaped member in question and the configurationof the eccentric sleeve, the markers for indexing may be formed ormoulded in the form of recesses into the edge region of the upper sideof the base plate, which edge region surrounds the opening for thesleeve. This may for example serve a useful purpose when the eccentricsleeve takes the form of a hold-down sleeve which carries on itscircumferential surface a projection which bears against the upper sideof the base plate in the fully installed state. However, fixing which isparticularly secure and safe against wear is obtained when the markersfor indexing are formed or moulded in the circumferential wall of theopening for the sleeve.

Regardless of where they are arranged, the markers for indexing may takethe form of recesses in groove form.

The markers for indexing may be arranged in a given pattern which ishelpful in the given application. In this way, it may be useful undercertain circumstances for the size of the stepped change in place fromone marker for indexing to the next to increase following a givenfunction, which size is fixed by the distance between two markers forindexing. However adjustability which is versatile and particularly easyfor the installer to follow is obtained if the angular intervals betweenmutually adjacent markers for indexing are each sized in such a way thateach adjustment in rotation of the eccentric sleeve seated in theopening for the sleeve involves a change of unvarying size in theposition of the base plate.

It also helps to simplify operation if one of the markers for indexingis defined as the “zero position” which forms the starting point for thechange in the position of the base plate when a fastener for a railwhich is formed using the base plate is being installed.

It also helps to save weight and to increase the stiffness of the baseplate if a stiffening structure formed by ribs and by depressionspresent between the ribs is formed or moulded in the underside of thebase plate, which underside is associated with the fixed bottom support.By closing off at least an adequate number, and in particular all, ofthe depressions of the stiffening structure with a filling material, itis possible in this case to avoid the risk of the stiffening structureimpressing itself into the elastic intermediate layer under load anddoing lasting damage to the latter. What is meant by “closing off” inthis connection is filling of the depressions in any way which ensuresthat, when the system is fully installed, the ribs on the base plate atmost impress themselves into the elastic intermediate layer only by anamount sufficiently small for no permanent damage to be done in the casewhere a load is applied by a railway vehicle travelling over thefastening point formed by the system.

Depending on the sensitivity and load-bearing capacity of the elasticlayer on which the base plate is to be placed, it may be useful for onlysome of the depressions to be filled with filling material. In this way,a procedure which suggests itself is, in cases where the depressions areregularly arranged, for one or more depressions to be left unfilledbetween two that are filled, provided that, under load, this does notcause a preset permitted load per unit area to be exceeded which ispreset to ensure permanent elastic behaviour by the elastic intermediatelayer. However, production becomes particularly simple and operationparticularly safe and reliable if all the depressions of the stiffeningstructure on a base plate according to the invention are filled withmoulding material.

Depending on the load-bearing capacity of the filling material, it maybe enough in this case if, in the form of a thin layer, it merely closesoff the given depression like a sort of lid at the opening thereof whichis associated with the underside. When this is the case the fillingmaterial may for example be a sufficiently thick film or foil or plateor sheet which closes off the opening of the given depression.

If however the depressions are to be filled in such a way thatparticular loads can be carried or if the filling material is, inaddition, to assist in sound damping or to perform some other additionalfunction, it may be equally useful for the depressions to be completelyfilled with the filling material or for sufficient filling material tobe placed in each of the depressions for the filling material to projectabove the ribs which define the given depression. Precisely in thelatter case, this gives a particularly reliable guarantee that inpractical operation no damage will be done to the elastic intermediatelayer by the ribs.

The filling in the form of the filling material can always be introducedinto the given depression in a separate stage of operations, such forexample as after the production of the base plate. For this purpose, thefilling material may be injected into the depressions in a flowablestate or may be inserted as a pre-manufactured shaped member.

What may be considered as a plastics material for the production of thebase plate is for example glass-fibre reinforced polyamide. What issuitable as a filling material on the other hand is unreinforcedpolyamide.

Excessive compression of the elastic intermediate layer when under loadmay also be prevented by forming on the underside of the base plate, atthe underside thereof, at least one projection which points away fromthe underside and which acts as a stop and by which, when the system isfully installed, a limit is set for the travel by which the base platesinks, as a result of the elasticity of the elastic intermediate layer,when a railway vehicle travels over the rail. The projection concernedmay extend round the base plate in this case after the fashion of anapron which projects towards whatever is the fixed bottom support in thegiven case, thus ensuring that there is on all sides a stop for thesinking movement of the base plate regardless of the movement which itmakes in the given case. A surrounding projection of this kind has theadditional advantage that it protects the elastic intermediate layeragainst fouling and moisture. However, it is of course equallyconceivable for a separate projection to be provided for the samepurpose at each of given points.

Alternatively or in addition, the function described above of aprojection formed on the base plate may also be performed by aprojection formed on the carrier plate which, when the carrier plate isin the installed state, points towards the base plate and by which, whenthe system is fully installed, a limit is set for the travel by whichthe base plate sinks, as a result of the elasticity of the elasticintermediate layer, when a railway vehicle travels over the rail. At thesame time, the projection on the carrier plate may, if suitablyconfigured, form a receptacle for the elastic intermediate layer. Thisis particularly true if the projection concerned extends along the edgeof the intermediate layer for at least a sufficient proportion of thecircumference of the latter or if an adequate number of separateprojections which fix the position of the intermediate layer arearranged on the carrier plate.

The bracing of the resilient member which is required in each case tohold down the rail may also be accomplished, in a system according tothe invention, by forming or moulding in the base plate athrough-opening which runs from the upper side of the base plate to itsunderside and through which the clamping bolt can be inserted from theunderside.

In order on the one hand to easily ensure in this case that thefastening bolt is securely held during the operation of bracing theresilient member and on the other hand to prevent the elasticintermediate layer from being loaded by a bolt head which projects fromthe underside of the base plate, a receptacle may also be formed ormoulded in the underside of a base plate designed in accordance with theinvention in the region of the mouth of the through-opening, in whichreceptacle the polygonal, and in particular hexagonal, head of theclamping bolt is seated in the fully installed state.

So that the clamping bolt whose head is seated in the receptacle is ableto withstand even the high torques which may be generated when the givenresilient member is being braced without separate metal members or thelike having to be inserted for this purpose in the base plate which ismade of plastics material, the invention proposes, in a furtherembodiment which is important from the practical point of view, thateach side-face of the bolt head have associated with it a face forcontact which is formed on the circumferential wall of the receptacle.This face for contact extends in this case for part of the length ofwhichever is the associated side-face of the bolt head, thus enablingthe relevant side-faces of the bolt head each to have, in the installedstate, planar support from the faces for contact respectively associatedwith them.

At the same time, the faces for contact on the circumferential wall arearranged, in this embodiment of the invention, to be spaced apart fromone another, thus enabling there to be formed or moulded in thecircumferential wall of the receptacle, between each pair of adjacentfaces for contact, a recess in the region of which there is no contactbetween the bolt head and the circumferential wall of the receptacle inthe fully installed state. What is achieved by a design of this kind forthe receptacle is that even under a torque load there is, between thesections of the receptacle which receive the load, planar contact bywhich the forces to be received are transmitted into the sections of thebase plate surrounding the receptacle over a comparably large area.

What are prevented in this way are the load peaks which occur inreceptacles of conventional design whose shape is a close match to theshape of the bolt head which they are to receive. Because of theinevitable clearance with which the bolt head is seated in itsassociated receptacle, what regularly arises in this case at the edgessituated between the side-faces of the bolt head is a narrow, linearregion of contact at which the entire load is concentrated. Thisconcentration of force may become so high that the bolt head works itsway into the material surrounding the receptacle and there is no longerany guarantee of the bolt head being securely held. With the planarsupport for the side-faces of the bolt head which is achieved inaccordance with the invention, this danger no longer exists.

Following the model provided by the prior art, the base plate which isprovided in a system according to the invention may have on its upperside a supporting surface for the rail which is to be fastened in place,which supporting surface is bounded by respective supporting shouldersat its longitudinal sides which are aligned in the longitudinaldirection of the rail which is to be fastened in place. To enabletolerances affecting the width of the foot of the rail to be compensatedfor or to provide additional adjustability for the track gauge, at leastone adapter piece may be provided to bridge the gap which exists in theinstalled state between the foot of the rail which is to be fastened inplace and the given supporting shoulder. To enable the adapter piece tobe fastened in place in the correct position in a easy way and one whichensures reliable operation, a shaped member may be provided on the baseplate which, in combination with a complementary shaped member formed onthe adapter piece, ensures that the adapter piece has a positive-fitgrip on the base plate.

To enable the rail which is to be fastened in place to be resilientlyand elastically supported relative to the base plate too in a way whichallows easy installation and is, at the same time, effective, an elasticintermediate layer may be applied to the supporting surface which ispresent on the base plate. A layer of an elastic moulding material mayfor example be sprayed onto the supporting surface.

Further minimising of the weight of the base plate can be achieved bygiving the base plate, when seen in plan, a constriction in the regionof the supporting surface. In this embodiment, when measured in thelongitudinal direction of the rail, the width of the base plate isgreater in the portions thereof which project beyond the rail laterallyin the installed position than in the region which is situatedunderneath the foot of the rail. In this way, not only is extra weightsaved but the wider lateral portions also contribute to providingoptimised support for the rail against the transverse forces which actwhen travel takes place over the system.

The installation of the system according to the invention can besimplified by providing at least one clip which, for installation, holdstogether in a pre-assembled position a pack made up of the base plate,the intermediate layer situated below it and the carrier plate situatedbelow the intermediate layer.

The invention will be explained in detail below by reference todrawings, which show an embodiment. In the drawings:

FIG. 1 is an exploded view of a system for fastening a rail in place.

FIG. 2 is a plan view of the system in the fully installed position.

FIG. 3 is a view of the system from one side, in the fully installedposition, looking in the longitudinal direction of the rail.

FIG. 4 is a perspective view of the system from one side in the fullyinstalled position.

FIG. 5 is a perspective view from above of a base plate and associatedeccentric sleeves.

FIG. 6 is a perspective view from below of the base plate havingeccentric sleeves inserted in it.

FIG. 7 is a perspective view of an eccentric sleeve.

FIG. 8 is a perspective view from below showing a first enlarged detailof the base plate.

FIG. 9 is a perspective view from below showing a second enlarged detailof the base plate.

The system 1 for fastening a rail S to a fixed bottom support 2 which isformed in the present case by a concrete sleeper (not shown) comprises abase plate 3 made of a plastics material, an intermediate layer 4 madeof an elastically yielding material which is to be arranged below thebase plate 3, a carrier plate 5 which is to be arranged, below theintermediate layer 4, on the fixed bottom support 2, four eccentricsleeves 6 a, 6 b, 6 c, 6 d which have associated with them respectivefastening bolts 7 a, 7 b, 7 c, 7 d which act as fastening members, tworesilient members 8 a, 8 b, two adapter pieces 9 a, 9 b, and twoclamping bolts 10 a, 10 b.

Seen in plan, the base plate 3 made of plastics material is of anelongated bone-like shape. Its outer regions 3 a, 3 b which adjoinrespective ones of its narrow sides are of a considerably greater widthB in this case, measured in the direction of the longitudinal extent Lof the rail S which is to be fastened in place, than its central region,the change in the width B from the narrower central region to theadjoining wide lateral regions 3 a, 3 b taking place along a continuousstep-free path.

In the central region, there is formed or moulded on the upper side O ofthe base plate 3 a supporting surface 3 c which extends in thelongitudinal direction L, which extends across whatever is the width Bof the narrower central region of the base plate 3 in the given case,and which is bounded laterally relative to the narrow sides of the baseplate 3 by respective shoulders 3 d, 3 e.

A dovetail-like projection 3 f which projects towards the shoulder 3 d,3 e situated opposite is formed on each of the faces for contact of theshoulders 3 e, 3 d, which faces for contact are associated with thesupporting surface 3 c. By a recess of complementary shape, respectiveones of the adapter pieces 9 a, 9 b may be fitted onto this projection 3f in order, if required, to bridge a gap between the latter and the footF of the rail S which is placed on the supporting surface 3 c and inthis way to ensure secure and reliable lateral guidance for the rail S.

Formed or moulded in the shoulders 3 d, 3 e, in a position which isclosely adjacent to the supporting surface 3 c and central relative tothe extent of the shoulders in the longitudinal direction L, arerespective through-openings 3 g, 3 h which run from the upper side O ofthe base plate 3 to its underside U. Inserted through thethrough-openings 3 g, 3 h from the underside U of the base plate 3 arerespective clamping bolts 10 a, 10 b which are configured after thefashion of a conventional hexagon-head bolt. The heads 10 c of theclamping bolts 10 a, 10 b are seated in this case in respectivereceptacles 3 i, 3 j which are formed or moulded in the underside U ofthe base plate 3 and which are arranged in the region of the mouths ofrespective ones of the through-openings 3 g, 3 h.

The receptacles 3 i, 3 j are each surrounded by a circumferential wall 3k which is integrally connected to the base plate 3. In their respectivecircumferential surfaces associated with the receptacles 3 i, 3 j, thereare formed on the circumferential walls 3 k six faces for contact 3 lwhich are distributed at equal angular intervals around the centres ofthe respective receptacles 3 i, 3 j and the length La of each of which,measured in the circumferential direction of the respective receptacles3 i, 3 j, is less than half the length Ls of the side-faces 10 d of thebolt head 10 c. Formed or moulded in the given circumferential wall 3 kbetween each pair of adjacent faces for contact 3 l is a recess 3 mwhich recedes into the circumferential wall 3 k relative to the facesfor contact 3 l. In the circumferential wall 3 k, there is formed ormoulded in addition in this case, adjacent to one of the faces forcontact 3 l which define each of the recesses 3 m, a load-relievingrecess 3 n formed after the fashion of a groove, while the recess 3 mmerges into the other face for contact which defines it at a relativelyshallow angle.

The regular distribution of the faces for contact 3 l, recesses 3 m andload-relieving recesses 3 n belonging to the respective receptacles 3 i,3 j, and their position and dimensions, are selected in such a way that,in the fully installed position (FIG. 8), the side-faces 10 d of thebolt head 10 c bear against respective ones of the faces for contact 3 land each of the edges 10 e of the bolt head 10 c which are presentbetween pairs of side-faces 10 d is arranged in the region of aload-relieving recess 3 n without being in contact with the givencircumferential wall 3 k.

In the same way, in the region of the recesses 3 m there is no contactbetween the bolt head 10 c and the given circumferential wall 3 k, whichmeans that it is only the faces for contact 3 l which receive thetorques acting on the bolt head 10 c during installation and inpractical operation. The bolt head 10 c is prevented from cutting intothe material of the circumferential wall 3 k in the region of its edges10 e in this way, and any damage to or destruction of thecircumferential wall 3 k as a result of overloading is also prevented.

The base plate 3 is therefore able to withstand without any problems thetorques which arise when the resilient members 8 a, 8 b, which take theform of a conventional ω-shaped clamping clip, are being braced. For theresilient members 8 a, 8 b to be braced, they are placed on the baseplate 3 in such a way that the threaded shanks of the clamping bolts 10a, 10 b respectively associated with them pass through the centre loopsof the resilient members 8 a and 8 b respectively and the free resilientarms of the resilient members 8 a, 8 b rest on the foot F of the rail.Then, by means of nuts 12 which are screwed onto the respective threadedshanks, the centre loops of the resilient members 8 a, 8 b are pressedtowards the base plate 3 until an adequate hold-down force is exerted onthe foot F of the rail.

In the region of each of its corners, there is formed or moulded in thebase plate 3 an opening 3 o for a sleeve which runs from the upper sideO of the base plate 3 to its underside U.

Seated in each of the four openings 3 o for sleeves is one of theeccentric sleeves 6 a-6 d which are produced from a sufficiently strongmaterial which is able to slide well when paired with the material ofthe base plate 3. These eccentric sleeves 6 a-6 d have a through-opening6 e which is eccentrically arranged relative to the centre axis Me ofthe given eccentric sleeve 6 a-6 d. Formed on the outer circumferentialsurface of each of the eccentric sleeves 6 a-6 d is a narrow indexableprojection 6 f whose axis extends parallel to the centre axis Me andwhich extends for the full height He of each of the eccentric sleeves 6a-6 d. The eccentric sleeves 6 a-6 d are designed in this case to act ashold-down sleeves, for which purpose they have, at their upper edgeassociated with the upper side O of the base plate 3, a projection 6 gwhich extends round in a circle after the fashion of a collar. In thefully installed state, the projection 6 g from the eccentric sleeves 6a-6 d bears against the upper side O of the base plate 3.

The four openings 3 o for sleeves are each surrounded by acircumferential wall 3 p which is formed by the plastics material of thebase plate 3. Formed or moulded in the circumferential wall 3 p atirregular angular intervals α are markers for indexing 3 q which takethe form of grooves, and whose axes extend parallel to the centre axisMh of the given opening 3 o for a sleeve, and whose shape iscomplementary to that of the indexable projection 6 f which is formed oneach of the eccentric sleeves 6 a-6 d.

The markers for indexing 3 q and the openings 3 o for sleeves are eachso designed in this case that the eccentric sleeves 6 a-6 d respectivelyassociated with them are guided in them by their indexable projections 6f as a sliding fit and with positive-fit, in such a way that theposition in rotation of the eccentric sleeves 6 a-6 d in the openings 3o for sleeves associated with them is fixed but at the same time arelative movement between the base plate 3 and the given sleeve 6 a-6 ddirected in the direction defined by the centre axis Me is possiblewithout any problems.

When the system 1 is being installed, one of the fastening bolts 7 a-7 dis inserted through the through-opening 6 e in each of the eccentricsleeves 6 a-6 d and is screwed into the anchor 11 of plastics materialwhich is inset into the fixed bottom support 2. In this way, thefastening bolts 7 a-7 d each create an axis of rotation about which theeccentric sleeve 6 a-6 d associated with them can be adjusted inrotation. Taking into account the eccentricity of the axis of rotationwhich is created in this way relative to the centre axis Mh of the givenopening 3 o for a sleeve, the angular intervals α between the markersfor indexing 3 q are of a size such that, when the base plate 3 is fullyinstalled, each adjustment in rotation between two markers for indexinginvolves a displacement of the base plate 3 in a direction at rightangles to the longitudinal extent of the rail S by a distance which isalways of the same size. In this way, the angular intervals α may forexample be so designed that each adjustment in rotation of the eccentricsleeves 6 a-6 d displaces the base plate 3 by one millimetre to allowthe track gauge to be adjusted.

Integrally formed or moulded on the base plate 3, to extend round theedge of the base plate 3, is an apron-like projection 3 r which pointsaway from the underside U. The projection 3 r acts as a stop formovements directed towards the fixed bottom support 2 which the baseplate 3 makes when a railway vehicle (not shown) travels along the railS standing on it.

Formed or moulded into the base plate 3, in that region of the undersideU which is not occupied by the openings 3 o for sleeves and theircircumferential walls 3 q or by the receptacles 3 i, 3 j, is astiffening structure 3 s which is formed by ribs 3 t which intersect atright angles and by depressions 3 u which are arranged between them. Thedepressions 3 u are filled in this case with a moulding material T whichis lightweight but dimensionally stable. The filling T of mouldingmaterial terminates in this case substantially flush with the free topof the ribs 3 t or projects beyond the top of the ribs for a distanceof, typically, at least 2 mm, and there are thus no longer any sharpprotruding edges of the ribs 3 t.

So that the rail S is also supported elastically directly against thebase plate 3, an elastic layer 3 v which is composed of a permanentlyelastic plastics material is sprayed onto the supporting surface 3 c.Alternatively, it is also possible for the elastic layer 3 v to beformed by a pre-manufactured pad of elastic material which is placeddown on the supporting surface 3 c and which is in particular adhesivelybonded thereto.

When seen in plan, the elastic intermediate layer 4 is of a shape whichcorresponds to the area occupied by the stiffening structure 3. When thesystem 1 is in the fully installed state, the stiffening structure 3therefore completely covers the intermediate layer 4. This being so,even under the load applied by a railway vehicle travelling along therail S, the filling T of filling material which is present in thedepressions 3 u of the stiffening structure 3 s ensures that the ribs 3t of the stiffening structure 3 s do not cut into the intermediate layer4. Instead, the base plate 3 is always supported on the elasticintermediate layer 4 over such a large area that an optimum resilientaction is maintained in the long term.

The thin carrier plate 5 which rests on the fixed bottom support 2serves to protect the elastic intermediate layer against abrasive wearand dirt and ensures that there is an even surface for it to rest on. Tosecure the elastic intermediate layer in place on the carrier plate 5, aprojection 5 a which follows the outline shape of the elastic layerforms, on the upper side of the carrier plate 5, which upper side isassociated with the base plate 3, a receptacle in which, when the system1 is fully installed, the intermediate layer 4 is seated inpositive-fit. In addition, the projection 5 a also acts in this case asa stop which sets a limit to the movements of the base plate 3 directedtowards the fixed bottom support 2 and which prevents any excessivecompression of the elastic intermediate layer 4.

The elastic intermediate layer 4 is also protected against being toohighly compressed when being installed by the fact that the height He ofthe eccentric sleeves 6 a-6 d, which are designed to act as hold-downsleeves and which stand on the carrier plate 5 in the fully installedstate, is selected to be such that the base plate 3 is only pressedagainst the elastic intermediate layer 4 with a defined force even whenthe fastening bolts 7 a-7 d are fully tightened. If the force concernedis to be very low, the height He of an eccentric sleeve is selected tobe one which corresponds to the thickness of the base plate 3 in theregion of the openings 3 o for sleeves plus the thickness of the elasticlayer in the relaxed installed state, less the thickness of theprojection 6 g.

REFERENCE NUMERALS

-   α Angular intervals-   1 System for fastening a rail S in place-   2 Bottom support-   3 Base plate-   3 a, 3 b Outer regions of the base plate 3-   3 c Supporting surface of the base plate 3-   3 d, 3 e Shoulders of the base plate 3-   3 f Projection-   3 g, 3 h Through-openings-   3 i, 3 j Receptacles in the base plate 3-   3 k Circumferential wall-   3 l Face for contact-   3 m Recess-   3 n Load-relieving recess-   3 o Opening for sleeve-   3 p Circumferential wall-   3 q Marker for indexing-   3 r Projection-   3 s Stiffening structure-   3 t Rib-   3 u Depression-   4 Elastic intermediate layer-   5 Carrier plate-   5 a Projection-   6 a-6 d Eccentric sleeves-   6 e Opening in sleeve-   6 f Indexable projection-   6 g Projection-   7 a-7 d Fastening bolts-   8 a, 8 b Resilient members-   9 a, 9 b Adapter pieces-   10 a, 10 b Clamping bolts-   10 c Bolt head-   10 d Side-face of bolt head 10 c-   10 e Edge of bolt head 10 c-   11 Anchor of plastics material-   12 Nut-   B Width of the base plate 3 at respective points-   F Foot of rail-   He Height-   L Longitudinal direction-   Me Centre axis of a given eccentric sleeve 6 a-6 d-   Mh Centre axis of a given opening 3 o for a sleeve-   O Upper side of the base plate 3-   S Rail-   T Moulding material-   U Underside of the base plate 3

1. A system for fastening a rail to a fixed bottom support, comprising:a base plate produced from a plastics material, an intermediate layerwhich is arranged between the base plate and the fixed bottom support, acarrier plate which is arranged between the intermediate layer and thebottom support, a resilient member to hold down the rail which is to befastened in place, a clamping bolt to brace the resilient member againstthe base plate, and a fastening member for fastening the base plate tothe fixed bottom support.
 2. The according to claim 1, wherein there isformed or moulded in the base plate at least one opening for a sleeve,in which the opening for a sleeve and a hold-down sleeve are put in asliding fit, the height of which hold-down sleeve is greater than thethickness of the base plate in the region of the opening for a sleeveassociated with it and which hold-down sleeve has a projectionprotruding from its circumferential surface which bears against thanupper side of the base plate in a fully installed state, and in that thefastening member is intended to be inserted through an opening of thehold-down sleeve.
 3. The system according to claim 2, wherein thehold-down sleeve takes the form of an eccentric sleeve, in that thereare formed, in the opening for the sleeve, markers for indexing whichare arranged at a spacing from one another such that, allowing for theeccentricity of an axis of rotation of the eccentric sleeve from acentral longitudinal axis of the opening for the sleeve, the markers forindexing define positions in rotation of the eccentric sleeve if theeccentric sleeve is adjusted in rotation about its axis of rotation inthe opening for the sleeve, which positions in rotation correspond to astep-by-step change in the position of the base plate by a definedamount, and in that the eccentric sleeve has a shaped membercorresponding to the markers for indexing in the opening for the sleeveby means of which shaped member the eccentric sleeve inserted in theopening for a sleeve associated with the said eccentric sleeve iscoupled by positive-fit to a given one of the markers for indexing inthe opening for the sleeve.
 4. The system according to claim 1, whereina stiffening structure formed by ribs and by depressions present betweenthe ribs is formed or moulded in an underside of the base plate, whichunderside is associated with the fixed bottom support, and, whereindepressions of the stiffening structure are closed off with a fillingmaterial.
 5. The according to claim 1, wherein the intermediate layer iselastic and, wherein there is formed on an underside of the base plateat least one projection which points away from the underside and bywhich, when the system is fully installed, a limit is set for the travelby which the base plate sinks, as a result of elasticity of the elasticintermediate layer, when a railway vehicle travels over the rail.
 6. Thesystem according to claim 1, wherein the intermediate layer is elasticand, wherein there is formed on the carrier plate a projection which,when the carrier plate is in an installed state, points towards the baseplate and by which, when the system is fully installed, a limit is setfor the travel by which the base plate sinks, as a result of elasticityof the elastic intermediate layer, when a railway vehicle travels overthe rail.
 7. The system according to claim 6, wherein the projection onthe carrier plate forms a receptacle for the elastic intermediate layer.8. The system according to claim 1, wherein: there is formed or mouldedin the base plate a through-opening which runs from an upper side of thebase plate to an underside of the base plate and through which theclamping bolt can be inserted from the underside, a receptacle is formedor moulded in the underside of the base plate in the region of the mouthof the through-opening, in which receptacle a polygonal head of theclamping bolt is seated in a fully installed state, the polygonal headcomprising side faces, and each side-face of the bolt head hasassociated with it a face for contact which is formed on acircumferential wall of the receptacle and which extends for part of thelength of whichever is the associated side-face of the bolt head andagainst which the relevant side-face of the bolt head has, in theinstalled state, planar support, the faces for contact on thecircumferential wall being arranged to be spaced apart from one anotherand there being formed or moulded in the circumferential wall of thereceptacle, between each pair of adjacent faces for contact, a recess ina region of which there is no contact between the bolt head and thecircumferential wall of the receptacle in the fully installed state. 9.The system according to claim 1, wherein the base plate has on an upperside a supporting surface for the rail which is to be fastened in place,which supporting surface is bounded by respective supporting shouldersat its longitudinal sides of the supporting surface which are aligned ina longitudinal direction of the rail which is to be fastened in place.10. The system according to claim 9, wherein at least one adapter pieceis provided to bridge a gap which exists in an installed state between afoot of the rail which is to be fastened in place and the givensupporting shoulder.
 11. The system according to claim 10, wherein theadapter piece can be detachably coupled by positive-fit to thesupporting shoulder which is associated with it in the given case. 12.The system according to claim 9, wherein an elastic layer on which therail stands in the fully installed state is applied to the supportingsurface.
 13. The system according to claim 1, wherein at least one clipis provided which, for installation, holds together in a pre-assembledposition a pack made up of the base plate, the intermediate layersituated below it and the carrier plate situated below the intermediatelayer.
 14. A fastener for a rail, formed by a system designed inaccordance with claim 1.